The present invention relates, in general, to a typewriter system for typing text material in the Japanese language and more particularly to a system for creating and/or copying text material using touch-typing techniques, wherein a portion of the text is typed directly by the operator, and the remainder is produced automatically by the system from memory in response to addressing command inputs by the operator.
The typing of the Japanese language presents unique problems since the written language is unusually complex in that it uses a mixture of four different symbol systems and more than three thousand symbols are required. This complexity has hindered the development of effective technology for creating and copying texts written in Japanese. Mechanical typewriters which provide key-driven type elements have been developed, but they are flawed in two ways. Either their designs are too complex or they are too simple. With a complex design, utilizing a keyboard on which all four symbol sets are mapped, an operator can produce normal looking texts, but cannot touch-type because he must hunt-and-peck the symbols for his text from among several thousand alternatives. A simple design, on the other hand, uses a keyboard on which only a small subset of symbols are mapped. An operator can touch-type, but cannot produce normal-looking texts; what he does produce is strange-looking because it is symbolically impoverished.
In comparison, alphabetic typewriters, such as those used for typing the English language, enable operators to produce normal-looking texts as well as to make use of touch-typing techniques. Furthermore, such typewriters have the flexibility to accommodate novices who hunt-and-peck and experts who touch-type equally well. This is so because the knowledge an operator acquires early in his education relating to the rules of spelling and punctuation, and which are incorporated into other activities, are used in operating the typewriter, and these knowledges, together with practice, are all that are required to become an expert with such typewriters.
A typing system that duplicates the flexibility of alphabetic typewriters and at the same time produces a normal-looking product is needed for the Japanese language. Although much of the technology to make such a system operable is now available and has been used to produce automated typing systems for the Japanese language, presently available systems remain inadequate. For example, some existing systems rely on codes which must be memorized for each symbol, the codes being typed one by one into the system to identify the symbols to be produced in a text. With such systems, operators can touch-type and can produce normal-looking written text; on the other hand, they must undergo lengthy special training before they can use the system, and must practice constantly in order to maintain their skill. Such systems not only may be fatiguing, but are completely unintelligible to the novice typist, and thus they are not easily usable by various typists having a wide range of skill levels.
Other available systems oversimplify the operator's job. Operators are required to type only the phonetic equivalent of the text to be produced, and to identify which segments are to be represented by one symbol subset or another in the written text. The system does the rest. Operators can touch-type for short stretches and produce normal-looking written text material; however, the input produced by the typist is often ambiguous and the system can only make an educated guess, often based on a frequency count, concerning the intended symbol. Therefore, operators are forced to monitor the system continually, and often must interrupt their typing in order to correct the mistakes made by the system. This is a source of fatigue, and also prevents operators from ever being able to touch-type uninhibitedly.
Any Japanese sentence can be spelled out with either of two types of Japanese phonetic symbol systems, Hiragana and Katakana, which are referred to collectively as "kana". Hiragana are cursive letters made with flowing strokes and which represent syllables (i.e., combinations of consonants and vowels). Katakana are block letter symbols used to represent the same syllables as hiragana. The hiragana syllabary consists of 48 cursive symbols and 2 diacritics. Some examples of hiragana are: